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Full text of "Alaskan glacier studies of the National Geographic Society in the Yakutat Bay, Prince William Sound and lower Copper River regions"

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CHAPTER XX CHILDS GLACIER
General Description. Childs Glacier (Map 9), entering Copper River valley from the just north of Goodwin Glacier, at the head of the Copper River delta, ends in the river in a vertical ice cliff from 200 to 300 feet high. This ice cliff is all that one sees of the glacier from the railway bridge or from the river bank near Miles Glacier railway station. The ice cliff is so imposing that it has led some visitors to believe that Childs is larger than Miles Glacier, which is farther away, when as a matter of fact Childs Glacier is less than half as large.
The ice tongue is about ten or twelve miles long, rising in cirques and on snowy divides six. or eight thousand feet above sea level (PI. CXLVII), and is fed by at least five tributaries. The width of the valley glacier (Fig. 58) varies from a little over one to a little less than two miles, the narrowest part being near the mouth of the^mountain valley. East of this constriction (Fig. 57) the glacier expands into a small imperfect bulb in the Copper River valley, increasing in width from a mile and an eighth to over three miles in a distance of less than two miles. The low, sloping northern and southern margins of the glacier end on the land, being faced on each side by an alluvial fan; but in the middle the glacier terminates in Copper River, whose depth in front of the ice cliff is from 10 to 20 feet, and whose undercutting action has produced precipitous ice cliffs ior a distance of over two and a half miles.
The glacier surface is, in the main, clean and white, excepting along the terminal margins, and along the narrow lateral moraines extending up the glacier from these. There are four or five weak medial moraines, coming from the junction of tributaries in the mountains and curving irregularly with the flow of the ice in the expanded bulb. These medial moraines are not conspicuous features on the terminal cliff.
From its terminus to the snowfields, the glacier is severely crevassed, excepting in the northern and southern margins of the bulb where, up to 1909, the crevassing was so slight that the ablation moraine completely mantled the ice and even supported a few shrubs and annual plants. From the mouth of the mountain valley to the margin of the bulb, the slope of the lower portion of the glacier is 382 feet to the mile, an elevation of 1600 feet above sea level being reached less than three miles from the river. Above this the slope may be steeper, though the glacier maintains a moderately low grade as far as seen. There are, however, a number of cascading tributaries.
If Childs Glacier valley hangs in relation to the main Copper River valley it is completely masked by the glacial deposits. The walls of the glacier valley (Fig. 57) rise steeply to elevations of from three to six thousand feet in a short distance, as is well .shown north of the terminus, where a spur on the slopes of Mt. O'Neel1 (PL CLUE)
i A 6400 foot peak named in 1910 for Mr. A. C. O'Neel, chief bridge engineer of the Copper Eiver and Northwestern Railway, who built the steel bridge across the Copper River near the base of this mountain.
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